Dr. Kenneth Pienta Laboratory

Tumor Microenvironment Grant: Mechanisms of Tumor

prostate cancer

Legend: Prostate Cancer is a common neoplasm and the second leading cause of cancer deaths in American males. The high mortality rate is due mainly to the spread of malignant cells to many tissues including bone.
This photograph demonstrates molecular mimicry of PCa cells which may facilitate their ability to evade detection. Here, human PCa cells in the marrow of a severe combined immune deficient (SCID) mouse are shown to express the transcription factor Runx2, is normally expressed by marrow osteoblasts. The obliteration of the normal runx2 signal demonstrates that "the monster within" has taken over the marrow.
The image is a differential interference contrast (DIC) microscopy photograph overlaid with PCa cells stained green (using an antibody to human leukocyte antigens (HLA) – A,B,C). Runx-2 is stained with an antibody hooked to a red fluorochrome. Almost no red was observed and only green (PCa) or yellow (Red and green or PCa expressing Runx2) is seen.

Mechanisms of Prostate Cancer Dormancy in the Bone Marrow Niche





Yusuke Shiozawa  Shiozawa@umich.edu

Mr. W. is a 66 year old man. Six years ago he w/as diagnosed with a moderately differentiated, localized prostate cancer (PCa) when he presented for  routine physical exam and was found to have a prostate specific antigen (PSA) blood test of 5.2. Digital rectal exam revealed no abnormalities but prostate ultrasound and biopsy revealed a Gleason 4+3 = 7 cancer in 2/12 biopsy cores (clinical stage TIcNxMx). Because Mr. W. was in otherwise excellent health, he chose to undergo a radical retro pubic prostatectomy and his prostate was removed. All of his lymph nodes were negative for cancer. He was considered to be cured of his disease. One year ago, Mr. W.'s PSA became detectable and he now has 3 lesions present on bone scan. He has metastatic prostate cancer, now incurable. Each year, approximately 40,000 men who "should" have been cured of their prostate cancer by surgery or radiation therapy present with incurable metastatic disease that will manifest itself as metastatic lesions in the bone, usually years after primary treatment. The only explanation for this is that disseminated tumor cells (DTCs) are present in the bone microenvironment before surgery or radiation eradicated the primary tumor. Clearly the ability of DTCs to proliferate, undergo apoptosis or become dormant must occur soon after the initial arrest of circulating tumor cells (CTCs) in the marrow. Unquestionably, a greater understanding of the molecular events that regulate a DTCs ability to become, and remain dormant over long periods is crucial to define new therapeutic strategies to combat disease progression. How these cells traffic to the bone, become dormant, and then ultimately begin to proliferate is the subject of this TMEN application. The proposed TMEN is composed of highly interactive and complementary projects that are supported by a Human Sample Acquisition Core (HSAC). Ultimately this work will lead to defining new therapeutic strategies to combat PCa skeletal metastases. The findings generated by this program will lead to a significant impact on the health and well being of men with PCa. The global hypothesis Is that DTCs target the hematopoietic stem cell (HSC) niche during metastasis. Once In the niche the niche regulates dormancy of DTCs. When DTCs are able to overcome the growth regulatory effects of the HSC niche, metastatic foci develop.



© The Johns Hopkins University, The Johns Hopkins Hospital, and Johns Hopkins Health System. All rights reserved. Disclaimer
Email: webmaster@urology.jhu.edu | 600 North Wolfe Street, Baltimore, Maryland 21287

urology second opinion urology second opinion